Foots oil oxidate composition



United States Patent FOOTS OIL OXIDATE COMPOSITION John Walter Nelson, Lansing, 111., assignor to Sinclair Refining Company, New York, N. Y., a corporation of Maine No Drawing. Application February 16, 1954, Serial No. 410,709

6 Claims. (Cl. 260-451) My invention relates to novel oxidates of particular foots oil fractions obtained in the separation of the waxy components of petroleum which are particularly useful as rust inhibitors for distillate fuels.

The foots oil oxidates of my invention are characterized by improved stability, good oil solubility and good rust inhibiting properties and by a relatively low melting point within the range of about 80 to 95 R, an API gravity of about 10 to 25 and a saponification number of about 200 to 325. In appearance, the oxidates are waxy solids that are light amber to brown in color. The oxidates are particularly useful as low pour point rust inhibitors for distillate fuels, for example, gasoline.

Useful foots oil oxidate rust inhibitors for distillate fuels must have a combination of desirable properties. The properties of high saponification and acid number, low pour point and relatively light color are particularly important. The nature of the starting material is important in that it must produce a composition of these properties, and in addition, the factors of rate of oxidation and the cost of the starting material are important economically.

I have found that the oxidates described above having the desirable properties of a good low pour point rust inhibitor can be prepared by the controlled oxidation of particular foots oil fractions obtained from solvent deoiling or sweating of wax, e. g. slack wax. These particular foots oil fractions are characterized by a melting point within the range of about 80 to 120 R, an oil content of about 4 to 30 percent and an API gravity of about 30 to 45. Foots oil fractions obtained in this manner and having these properties are necessary to obtain foots oil oxidates having the combination of properties desirable for a low pour point rust inhibitor. Other foots oil fractions not having the above properties do not produce satisfactory products. The foots oil fractions obtained from the sweating of wax useful in my invention can be the liquid fraction separated from the first sweating of slack wax operation or the liquid separated from r e-sweating the liquid from the first sweating or any liquid from further re-sweatings, having the above defined characteristics. A foots oil fraction obtained by deoiling slack wax with methylethyl ketone, for example, single deoiling slack wax of a viscosity of about 60 to 70 Saybolt Universal seconds at 210 F., is a particularly advantageous starting material, although a fraction produced by double deoiling is also satisfactory.

I have also found that the particular foots oil fractions described above are easy to oxidize, that is, the oxidation rate is fast and generally lower temperatures may be used. Apparently, the oil present in the foots oil fraction contributes to the easy oxidizability of the foots oil fraction at a lower temperature. Thus, the oxidates of my in vention are produced easily from low cost foots oil and provide useful low pour point rust inhibitors for distillate fuels.

The foots oil oxidates are prepared by oxidizing a foots oil fraction obtained and having properties as described above by subjecting the foots oil to large amounts of air or oxygen at an elevated temperature, i. e., above about 250 F., in the presence of about 0.2 to 1.7 weight percent of an oxidation catalyst, e. g. potassium permanganate, for a period of time sufiicient to effect substantially complete oxidation of the foots oil. For example, a foots oil fraction obtained as described above and having a melting point of about to R, an oil content of about 4 to 30 percent and an API gravity of about 30 to 45 is oxidized with oxygen in the presence of potassium permanganate. The reaction is carried out at about 250 to 300 F. with, for example, about 165 liters of oxygen per kilogram of foots oil per hour using about 0.85 percent by weight of potassium permanganate. The reaction is continued until the oxidation is substantially comple'te, for example, until the reaction mixture has a saponification number of about 250 to 300. The oxidate is then separated, for example, by filtration.

The potassium permanganate catalyst is preferably prepared in situ. This may be done by adding a solution, e. g. water solution, of the catalyst to the foots oil at a temperature below the boiling point of the solvent and then evaporating the solvent by slowly raising the temperature of the foots oil and catalyst mixture with agitation. Preferably, however, the catalyst is prepared in situ by adding a solution of the catalyst in a solvent, e. g. water, to the foots oil while maintaining the foots oil at a temperature substantially above the boiling point of the solvent, i. e. above about 250 F. and preferably at about 300 to 360 F. when water is the solvent, as described in my pending application Serial No. 410,710, filed February 16, 1954. In this procedure, on contact of the catalyst solution with the heated foots oil, the solvent is rapidly flashed off and the catalyst is present in such great dilution that surprisingly, it does not react violently with the foots oil. In this procedure, foaming is kept to a minimum and the catalyst is thus prepared more rapidly than the slow solvent evaporation method and the oxidation rate is increased and the product color is improved. Al though water is the preferred solvent, organic solvents such as ketones, for example, acetone or methylethyl ketone, or mixtures thereof with Water may be used.

In the product are found monoand di-basic acids, hydroxy acids, normal esters, lactones, lactides, alcohols, ketones, carbon dioxide, carbon monoxide, water and some unreacted hydrocarbons. Due to the varying molecular weight of the feed stocks, and to their cleavage during oxidation, all of the organic compounds above occur within a Wide range of molecular weights. During the course of the reaction the low molecular weight volatile organic compounds, and carbon monoxide, carbon dioxide and water are collected overhead. Thus, except for trace amounts, they are not present in the solid reaction product.

While the crude oxidate is useful as such as a good rust inhibitor for distillate fuels, it is desirable to purify the oxidate to remove impurities in the form of inorganic compounds formed by the catalyst and low molecular weight corrosive acids. Thus, the crude oxidate must be used in larger concentrations to be effective and also the amount must be carefully controlled so that the concentration of corrosive acids does not become excessive, while a purified oxidate can be used in smaller and safe amounts. The crude oxidate, having a saponification number of about 250 to 325, is purified to produce a purified oxidate of a saponification number of about 200 to 250. Similarly, the acid number of the crude oxidate is reduced from about to 200 to about 100 to 150 for the purified oxidate.

Advantageously, the purification is carried out according to the method of my pending application Serial No. 410,711, filed February 16, 1954, now U. S. Patent No. 2,723,988, by first subjecting the crude oxidate to filtration, washing the filtered oxidate with watercontaining at least about 0.5 weight percent of hydrochloric'acid based on the weight of the oxidate and in a water to oxidate ratio of at least about 0.6 to 1, and stripping the filtered and washed oxidate at a tempe ature of about 225 to 275 F. with steam in an amount of at least about 100 weight percent of the weight of the oxidate.

The oxidates of my invention will be further illustrated by reference to the following example.

From 2,000 to 2,400 grams of a foots oil fraction having the properties described below in Table I were charged into a reactor flask. The foots oil was heated and then about 085 Weight percent of seed, a product from a previous reaction, was added. The mixture was then heated to 300 to 325 F. while stirring. Meanwhile, 0.85 weight percent of potassium permanganate was dissolved in five times its weight of warm water. This catalyst solution at about 150 to 170 F. was added dropwise to the agitating foots oil and seed. The water was flashed off during the catalyst addition. Oxygen at the rate of 165 liters per hour per kilogram of foots oil was then introduced. When overhead started to form and the temperature rose, the flask was cooled to the run temperature of 250 to 260 F. This temperature was maintained until the saponification number of the product was approximately 300. The reaction started from 1 to 30 minutes after the introduction of the oxygen. Upon completion of the oxidation, the product was filtered by vacuum through a pad of clay.

The filtered crude product was then analyzed and tested for rust preventive properties in gasoline. In this procedure, a freshly ground rust test coupon consisting of a /2 inch diameter by /2 inches long mild steel rod is suspended in a 400 m1. beaker equipped with a stirrer and placed in a temperature controlled bath capable of maintaining the temperature at 100il F. The test fuel (350 ml.) containing the rust inhibitor is added and stirred for thirty minutes to allow rust inhibitor to precoat the test specimen. Part (50 ml.) of the test fuel is then removed and 30 cc. of distilled water is added, and the mixture stirred for a 3 /2 hour test period. At the end of this period, the coupon is removed, dried with suitable solvents, inspected and rated according to the following scale:

A No rust.

B++ Trace of rust (covering a maximum of 0.25% of total surface area).

B+ Less than 5% of surface area covered by rust.

B 5 to 25% of surface area covered by rust.

C 25 to 50% of surface area covered by rust.

D 50 to 75% of surface area covered by rust.

E 75 to 100% of surface area covered by rust.

The test conditions are substantially more severe than ordinary conditions encountered so that results give a clear indication of the effectiveness of the inhibitor mixture.

The properties of the foots oil fractions and the properties of the resulting oxidate as well as its effectiveness as a rust preventive for gasoline are listed below in Table I. In Table I, Sample No. 1 was a foots oil fraction having a melting point of 116 F. obtained from the drips of the fifth re-sweating step in the sweating of slack wax. Sample No. 2 was a foots oil having a melting point of 85 F. obtained from the methylethyl ketone single deoiling of slack wax having a viscosity of 65 SUS at 210 F. Sample No. 3 was a foots oil fraction having a melting point of 105 F. obtained from the methylethyl ketone double deoiling of slack wax having a viscosity of 65 SUS at 210 F.

Table I Sample Number Foots Oil Grams 2 000 2,000

Saporiificatlon No. 0 Acid No 0 0 0 I2 N0 1. 8 8. 0 5. 5 Percent 011 3. 82 27. 99 22. 62 API Gravity 42. 2 33. 5 3G. 1 Pour Point, F... 115 85 105 Oxidate, Grams 2,111 1,800 1, 802 saponification N0 206. 2 282. 8 293. 5 Acid N0 184. l 160. 2 182. 2 I2 N0 3. 4 a. 5 7 API Gravity 19.4 11.3 14 Four Point, F. 95 85 95 Percent, Uusaponifiahlesnn 24. 37 13. 59 14. 82 2. 5 4 44. 5 J1. 32. 75 88.0 90. o 00. 1 Rust. 1Irnh/flntor lGaso JS. 1000 s. B++ B++ B 4 lbs/1,000 bhls B++ A A The results tabulated in Table I show that the foots oil fractions are easily oxidized and that the oxidates have good color, high saponification and acid numbers and low pour points and are excellent rust inhibitors for gasoline.

I claim:

1. As a novel composition of matter, an oxidate of a foots oil fraction selected from the group consisting of foots oil fractions obtained by the solvent deoiling of wax and foots oil fractions obtained from the sweating of wax, said foots oil fraction having a melting point within the range of about to 120 F., an oil content of about 4 to 30 percent and an API gravity of about 30 to 45, which oxidate is characterized by a melting point within the range of about 80 to F., an API gravity of about 10 to 25 and a saponification number of about 200 to 325.

2. As a novel composition of matter, a purified oxidate of a foots oil fraction selected from the group consisting of foots oil fractions obtained by the solvent deoiling of wax and foots oil fractions obtained from the sweating of wax, said foots oil fraction having a melting point within the range of about 80 to F., an oil content of about 4 to 30 percent and an API gravity of about 30 to 45, which oxidate is characterized by a melting point within the range of about 80 to 95 F., an API gravity of about 10 to 25 and a saponification number of about 200 to 250.

3. As a novel composition of matter, an oxidate of a foots oil fraction obtained by the solvent deoiling of wax and having a melting point within the range of about 80 to 120 F., an oil content of about 4 to 30 percent and an API gravity of about 30 to 45, which oxidate is characterized by a melting point within the range of about 80 to 95 F., an API gravity of about 10 to 25 and a saponification number of about 200 to 325.

4. As a novel composition of matter, a purified oxidate of a foots oil fraction obtained by the solvent deoiling of wax and having a melting point within the range of about 80 to 120 F., an oil content of about 4 to 30 percent and an API gravity of about 30 to 45, which oxidate is characterized by a melting point within the range of about 80 to 95 F., an API gravity of about 10 to 25 and a saponification number of about 200 to 25 0.

5. As a novel composition of matter, an oxidate of a foots oil fraction obtained from the sweating of wax and having a melting point within the range of about 80 to 120 F., an oil content of about 4 to 30 percent and an API gravity of about 30 to 45, which oxidate is characterized by a melting point within the range of about 80 to 95 F., an API gravity of about 10 to 25 and a saponification number of about 200 to 325.

6. As a novel composition of matter, a purified oxidate ized by a melting point within the range of about 80 to 95 R, an API gravity of about 10 to 25 and a saponification number of about 200 to 250.

References Cited in the file of this patent UNITED STATES PATENTS Hofmann June 10, Pollock Jan. 9, Beller et a1. Oct. 1, Gerlicher Feb. 24, Hirsch Dec. 18, Kirk et a1 June 29, 

1. AS A NOVEL COMPOSITION OF A MATTER, AN OXIDATE OF A FOOTS OIL FRACTION SELECTED FROM THE GROUP CONSISTING OF FOOTS OIL FRACTIONS OBTAINED BY THE SOLVENT DEOILING OF WAX AND FOOTS OIL FRACTIONS OBTAINED FROM THE SWEATING OF WAX, SAID FOOTS OIL FRACTION HAVING A MELTING POINT WITHIN THE RANGE OF ABOUT 80 TO 120* F., AN OIL CONTENT OF ABOUT 4 TO 30 PERCENT AND AN API GAVITY OF ABOUT 30 TO 45, WHICH OXIDATE IS CHARACTERIZED BY A MELTING POINT WITHIN THE RANGE OF ABOUT 80 TO 95* F., AN API GRAVITY OF ABOUT 10 TO 25 AND A SAPONIFICATION NUMBER OF ABOUT 200 TO
 325. 